1. Field of the Invention
The present invention relates to a carrier recovery apparatus and a related method, and more particularly, to a carrier recovery apparatus and a related method selectively allowing a pilot-based FPLL or a pilot-less PLL to perform the carrier recovery on an input signal according to a pilot strength of the input signal.
2. Description of the Prior Art
In many communication systems, a pilot is purposely added to facilitate carrier recovery at the receiver side. For these systems, a conventional pilot-based frequency and phase lock loop (FPLL) is typically used to achieve both wide acquisition range and fast acquisition speed. However, under fading channels, if the pilot is severely attenuated or even notched due to fading, the conventional pilot-based FPLL will lose lock and cause disruption in reception.
In order to solve such problem, different proposals for pilot-less FPLL are already disclosed in the past years. Nevertheless, these proposals are too complicated to be practically implemented and spend higher cost. Hence, how to overcome such drawbacks and how to reduce cost become an important topic of the field.